A red water occurrence in drinking water distribution systems caused by changes in water source in Beijing,China: mechanism analysis and control measures

A red water phenomenon occurred in several communities few days after the change of water source in Beijing, China in 2008. In this study, the origin of this problem, the mechanism of iron release and various control measures were investigated. The results indicated that a significant increase in sulphate concentration as a result of the new water source was the cause of the red water phenomenon. The mechanism of iron release was found that the high-concentration sulphate in the new water source disrupted the stable shell of scale on the inner pipe and led to the release of iron compounds. Experiments showed that the iron release rate in the new source water within pipe section was over 11-fold higher than that occurring within the local source water. The recovery of tap water quality lasted several months despite ameliora- tive measures being implemented, including adding phosphate, reducing the overall proportion of the new water source, elevating the pH and alkalinity, and utilizing free chlorine as a disinfectant instead of chloramine. Adding phosphate was more effective and more practical than the other measures. The iron release rate was decreased after the addition of 1.5 mg. L-1 orthophosphate- P, tripolyphosphate-P and hexametaphosphate-P by 68%, 83% and 87%, respectively. Elevating the pH and alkalinity also reduced the iron release rate by 50%. However, the iron release rate did not decreased after replacing chloramine by 0.5-0.8 mg. L-1 of free chlorine as disinfectant.     

Source apportionment of ambient PM10 in urban areas of Wuxi, China

A total of 168 PM₁₀ samples were collected during the year of 2005 at eight sites in the city of Wuxi in China. Fifteen chemical elements, three water-soluble ions, total carbon and organic carbon were analyzed. Six source categories were identified and their contributions to ambient PM₁₀ in Wuxi were estimated using a nested chemical mass balance method that reduces the effects of colinearity on the chemical mass balance model. In addition, the concentrations of secondary aerosols, such as secondary organic carbon, sulfate and nitrate, were quantified. The spatially averaged PM₁₀ was high in the spring and winter (123 ??g·m^?3 and low in the summer-fall (90 ??g·m^?3). According to the result of source apportionment, resuspended dust was the largest contributor to ambient PM₁₀, accounting for more than 50% of the PM₁₀ mass. Coal combustion (14.6%) and vehicle exhaust (9.4%) were also significant source categories of ambient PM₁₀. Construction and cement dust, sulfates, secondary organic carbon, and nitrates made contributions ranging between 4.1% and 4.9%. Other source categories such as steel manufacturing dust and soil dust made low contributions to ambient PM₁₀.     

Phosphorus fractionation in surface water and sediments of industrially polluted freshwater reservoir,India

Industrial pollutions are responsible for alterations in biogeochemical cycling of phosphorus (P) in freshwater systems. The objectives of the present study were to quantify the major P forms and assess the relationship between P fractions in water and surface sediments of Govind Ballabh Pant Sagar (GBPS) reservoir, India. Surface water samples (n?=?48) and surface sediment samples (n?=?48) were collected from six regions of GBPS reservoir in December 2014. The results showed that total particulate phosphorus (TPP) and total dissolved phosphorus (TDP) account for 45%–58% and 42%–55% of total phosphorus (TP) in the surface water. The authigenic-P was found to be more than 84% of the total P in surface sediments. The TPP showed a positive statistical relationship with sedimentary P fractions (authigenic-P, exch-P, and organic-P) indicated the impact of industrial pollution load on inorganic and organic P fractions in water and sediments of GBPS reservoir. The discriminant fraction analysis (DFA) revealed that the exch-P, Fe(III)-bound-P, detrital-P, organic-P, and TPP were sensitive indicators of P dynamics in the industrially polluted GBPS reservoir.     

Cephalodiscus sp. (Hemichordata: Pterobranchia): observations of functional morphology,behavior and occurrence in shallow water around Bermuda

A pterobranch hemichordate, Cephalodiscus sp., was collected from Bermuda just below the low-tide mark in July 1983 and again in October through December 1983. This is the third report of this genus in shallow water and the second for the Western Hemisphere. Specimens were observed alive in the laboratory. Colonies consist of zooids at various stages of development arranged in clusters inside a translucent, collagenous coenecium. Cilia-driven currents of the zooids are used in a method of filter-feeding similar to phylactolaemate bryozoans.     

Particle size distribution and pollutants in road-deposited sediments in different areas of Zhenjiang,China

An understanding of road-deposited sediment (RDS) characteristics on an impervious surface is essential to estimate pollutant washoff characteristics and to minimise the impacts of pollutants on the water environment. A total of 62 RDS samples were collected from four different land-use types (commercial, residential, intense traffic and riverside park) in Zhenjiang City, China. The samples were fractionated into seven grain-size classes and analysed for particle size distribution and concentrations of pollutants. The samples are found to consist predominantly of fine particles (60–80%, <250 μm). The maximum mean concentrations of zinc, lead and copper were 686.93, 589.19 and 158.16 mg/kg, respectively, with the highest metal concentrations found in samples from the intense traffic area. The maximum mean contents of organic matter (12.55%), nitrogen (6.31 mg/g) and phosphorus (5.15 mg/g) were found in samples from the commercial area. The concentrations of heavy metals were highest in the smallest particle size fraction analysed (63 μm). The organic matter and nitrogen content generally increased with decreasing particle sizes in the <500-μm particle size range. The results also revealed that most of the total nitrogen (TN) is attached to the finer sediments and that to effectively reduce TN loads in particulates, treatment facilities must be able to remove the finer particles (down to 125 μm for TN).     

Investigation of severe water problem in urban areas of a developing country: the case of Dhaka,Bangladesh

The present study evaluated water supply geochemistry in Dhaka City, Bangladesh, to provide detailed trace level (subppb) water quality data that include major ions, low dissolved oxygen (DO) and toxic trace metals for sustainable development. Dhaka Groundwater, which almost uniformly meets the World Health Organization guideline, has become the preferred source. Due to groundwater depletion and an ever-increasing need to meet water demands by city residents, Dhaka water supply and sewerage authority has initiated the treatment of river water, despite the fact that very little is known about the geochemical structure, and trace metal content in the Dhaka water supply. Major ion composition of water samples was determined, and the results used to generate Stiff diagrams. The diagrams served to visually compare water from different sources based on units of mass/volume. Hydrochemical facies analysis showed supply ground and surface waters are comprised predominately of Ca–Na–Mg–HCO₃ and Ca–Na–Mg–HCO₃–Cl types. Spatial distribution of ions, and Na/Cl and Na/SiO₂ molar ratio indicated that silicate weathering is the dominant geochemical process. Chemical data revealed that toxic Cr metal mobilization is associated with chemical hazards from the leather industry. The vulnerability of deep wells to contamination by As is governed by the geometry of induced groundwater flow paths and the geochemical conditions encountered between the shallow and deep regions of the aquifer. Quantifying total arsenic (As) and As from interlocking geochemical cycles (Fe, Mn) may assist in interpreting As dynamics in Dhaka well water. The surface source water was hypoxic to anoxic low DO associated with very high concentrations of biological oxygen demands, and electrical conductivity compared to industrial and non-industrial urban processes and standard activity guidelines. The results of this study should be applied to future research focused on the potential to improve water quality in urban and surrounding areas.     

Occurrence and hydrogeochemical characteristics of high-fluoride groundwater in Xiji County,southern part of Ningxia Province,China

Environmental Geochemistry and Health - High-F− groundwater is widely distributed in Xiji County, which endangers the safety of drinking water. In order to evaluate the key factors...     

Polycyclic aromatic hydrocarbons in farmland soils around main reservoirs of Jilin Province,China: occurrence,sources and potential human health risk

Study on the occurrence, sources and potential human health risk of polycyclic aromatic hydrocarbons in farmland soils around reservoirs is of great significance for the people drinking water security. In the present study, representative farmland soil samples around main reservoirs of Jilin Province, China, were investigated for 16 PAHs. The total concentrations of 16 priority PAHs in 32 farmland soil samples ranged from 602.12 to 1271.87 ng/g, with an arithmetic average of 877.23 ng/g, and the sum of seven carcinogenic PAH concentrations ranged from 30.07 to 710.02 ng/g, with a mean value of 229.04 ng/g. The 3-ring and 4-ring PAHs were major exist and account for 45.78 and 32.03%, respectively. Non-cancer and cancer risk of pollutants were calculated, and the results indicate that the complex PAHs in farmland soils were not considered to pose significant health effects. The isomer ratios Fla/(Fla + Pyr) and BaA/(BaA + Chr) show that the PAHs in soils were generally derived from biomass and coal combustion.     

Lead in Chinese coals: distribution,modes of occurrence,and environmental effects

Lead (Pb) has gained much attention since the 1970s because of its potential and cumulative toxicity. As one of the most hazardous elements in coals, Pb can be released into the environment during coal mining, processing, and utilization. This study presents a synthesis on the abundance, distribution, modes of occurrence, and environmental impacts of Pb in Chinese coals. Using the expected coal reserves as the weighting factor and based on the previously published Pb content in 4,304 coal samples (including results obtained in our laboratory) from main coalfields or coal mines in China, the weighted mean Pb content in Chinese coals is 13.0 μg/g, which is higher than that of the American coals (11 μg/g) and average world coals (7.8 μg/g). With respect to regional distribution of Pb in Chinese coals, Pb content can be arbitrarily divided into three groups (<20, 20–40, >40 μg/g). Following this classification, coals from Tibet have the highest average Pb content (128.94 μg/g). The abundance of Pb in coals varies with coal-forming periods and coal ranks, with the late Triassic and higher rank coals having the highest Pb content, which could be ascribed to regional geochemical differences and later geological evolution as well as magma hydrothermal activities. The enrichment of Pb in coals is influenced by several geological factors, including coal-forming plants, source rocks, hydrothermal fluid, and depositional environment. Pb, dominantly associates with sulfide minerals, especially galena in coals. During coal combustion or pyrolysis, Pb is partly emitted into the atmosphere and partly partitioned to solid residues. Accumulation of Pb from coal utilization in human body could lead to a range of health problems and increase the risk of cancer.     

Monitoring,mapping and health risk assessment of fluoride in drinking water supplies in rural areas of Maku and Poldasht,Iran

The aim of this study was to investigate and determine fluoride concentrations in drinking water supplies in rural areas of Maku and Poldasht in West Azerbaijan Province, the northwest of Iran. Fluorosis risk assessment and characterization was also investigated. Fluoride concentrations mapping was accomplished by using the GIS system. Totally, 356 water samples, including one sample in each season, were collected from 89 water supplies providing water for 95 and 61 rural areas of Maku and Poldasht, respectively. According to the results, in Maku and Poldasht, 25 and 30 rural areas had contaminated water sources, respectively. Average annual fluoride concentrations ranged from 3.04 to 7.31 mg/l in the contaminated villages of Maku, which is about 2–4.8 times higher than the maximum standard level of the Iranian drinking water standard, and 4.52–8.21 mg/l in the contaminated areas of Poldasht, which is about 3–5.47 times higher than the maximum standard level. The maximum fluoride level was determined 11.12 mg/l and 10.98 mg/l in one of villages of Maku and Poldasht Counties in summer, respectively. Neither in Maku nor in Poldasht, water resources showed dental cavity risk, while dental fluorosis risk and skeletal fluorosis risk were very significant in some villages of both cities. Children were at most risk of fluorosis. New alternative water supplies for the contaminated villages if possible, consumption of bottled water and application of reverse osmosis are recommended as remedial actions in the contaminated areas.

     

广州市典型中小型水库营养状态与蓝藻种群特征

中小型水库是广州市供水的重要水源地和后备水源地,为了解这类水库的富营养化特征以及蓝藻种群的动态,于2010年的枯水期、丰水期对广州市6座典型的中小型水库进行了采样与分析。结果表明：梅州水库、芙蓉嶂水库为贫-中营养型,三坑水库、百花林水库、和龙水库为中-富营养型,洪秀全水库为富营养型,水库营养状态指数季节变化差异不显著。在同一座水库中,水力滞留时间越长,营养状态指数越高;在不同水库之间,营养状态指数与集雨区内人类活动影响有关。6座水库蓝藻生物量的季节变化明显,受水温和水体稳定性的影响,枯水期蓝藻生物量在0.14~171.8μg.L-1之间,占浮游植物总生物量的0.1%~10.0%;丰水期蓝藻生物量在0.013~32.8 mg.L-1之间,占浮游植物总生物量的6.5%~97.0%。不同营养状态的水库之间蓝藻的生物量和种类差异明显,受营养盐和水力滞留时间的影响,梅州水库、芙蓉嶂水库蓝藻生物量在0.1~16μg.L-1之间,主要种类为泽丝藻（Limnothrix redekei）、卷曲鱼腥藻（Anabaena pertuthate）、水华微囊藻（Microcystis flos-aquae）、粘球藻（Gloeocapsa sp.）;三坑水库、百花林水库、和龙水库蓝藻生物量在0.057~32.8 mg.L-1之间,主要优势种为拟柱孢藻（Cylindrospermopsis raciborskii）、泽丝藻、假鱼腥藻（Pseudanabaena limnetica）;洪秀全水库蓝藻生物量在0.107~2.637 mg.L-1之间,主要优势种为阿氏颤藻（Oscillatoria agardhii）、水华微囊藻、卷曲鱼腥藻。     

Source apportionment and health risk assessment of potentially toxic elements in road dust from urban industrial areas of Ahvaz megacity,Iran

This study investigates the occurrence and spatial distribution of potentially toxic elements (PTEs) (Hg, Cd, Cu, Mo, Pb, Zn, Ni, Co, Cr, Al, Fe, Mn, V and Sb) in 67 road dust samples collected from urban industrial areas in Ahvaz megacity, southwest of Iran. Geochemical methods, multivariate statistics, geostatistics and health risk assessment model were adopted to study the spatial pollution pattern and to identify the priority pollutants, regions of concern and sources of the studied PTEs. Also, receptor positive matrix factorization model was employed to assess pollution sources. Compared to the local background, the median enrichment factor values revealed the following order: Sb > Pb > Hg > Zn > Cu > V > Fe > Mo > Cd > Mn > Cr ≈ Co ≈ Al ≈ Ni. Statistical results show that a significant difference exists between concentrations of Mo, Cu, Pb, Zn, Fe, Sb, V and Hg in different regions (univariate analysis, Kruskal–Wallis test p < 0.05), indicating the existence of highly contaminated spots. Integrated source identification coupled with positive matrix factorization model revealed that traffic-related emissions (43.5%) and steel industries (26.4%) were first two sources of PTEs in road dust, followed by natural sources (22.6%) and pipe and oil processing companies (7.5%). The arithmetic mean of pollution load index (PLI) values for high traffic sector (1.92) is greater than industrial (1.80) and residential areas (1.25). Also, the results show that ecological risk values for Hg and Pb in 41.8 and 9% of total dust samples are higher than 80, indicating their considerable or higher potential ecological risk. The health risk assessment model showed that ingestion of dust particles contributed more than 83% of the overall non-carcinogenic risk. For both residential and industrial scenarios, Hg and Pb had the highest risk values, whereas Mo has the lowest value.     

Spatial distribution of calcium in food, water and soil and its possible influence on rickets disease in Northern Nigeria

Since the 1990s, children of the Gbagyi tribe in Northern Nigeria have been suffering severe rickets with an incidence of up to 40% in the children's generation. The disease seems to be prevalent in an area of approximately 100 km(2) south-east of Kaduna. According to broad medical studies in that area, there is no evidence for a genetic disposition but for a nutritional cause of the disease. A lack of calcium was found in blood and was calculated to originate from diet. We therefore checked parent material, soil, maize cobs (Zea mays) and drinking water for their specific Ca contents from a region with rickets problem (study area A) and compared the results to Ca amounts in similar samples from a region where rickets is unknown among the Gbagyi population (study area B). It thereby became apparent that there are no differences in mineralogical composition of the parent material between the study areas, but that Ca contents in soil, maize cobs and drinking water are 47.6%, 26.6%, respectively, 79.1% lower in study area A compared to study area B. This result suggests that there may indeed be a nutritionally and/or environmentally influence on rickets disease. Nevertheless, further research on this topic is required.     

The effectiveness of travel restriction measures in alleviating the COVID-19 epidemic: evidence from Shenzhen,China

Environmental Geochemistry and Health - With the expansion of the global novel coronavirus disease (COVID-19) pandemic, unprecedented interventions have been widely implemented in many countries,...     

Exposure of ground water to alachlor,atrazine and metolachlor in maize areas of ribatejo and oeste (Portugal)

In irrigated maize areas of an important Portuguese agricultural area, Ribatejo and Oeste Region, alachlor, atrazine and metolachlor were detected in ground water.

During the study performed from 1996 to 1998 atrazine was the herbicide that showed the highest frequency of detection. In the 177 ground water samples collected 62% were contaminated with atrazine, 30% with alachlor and 12% with metolachlor. All these herbicides were detected both in ground water for human consumption and for irrigation, in some cases above 0.1 ug/L. The maximum levels quantified were 13μg/L for alachlor, 30μg/L for atrazine and 56 μg/L for metolachlor.

Seasonal variation of residues in ground water it is also presented through several examples of studies performed during the period 1991–1999.     

Stereoisomeric profiling of pharmaceuticals ibuprofen and iopromide in wastewater and river water, China

Stereoisomeric compositions can provide insights into sources, fate, and ecological risks of contaminants in the environment. In this study, stereoisomeric profiles of ibuprofen and iopromide were investigated in wastewater and receiving surface water of the Pearl River Delta, south China. The enantiomeric fraction (EF) of ibuprofen was 0.108–0.188 and 0.480, whereas the isomer ratio (IR) of iopromide was 1.426–1.673 and 1.737–1.898 in the influent and final effluent, respectively, suggesting stereoselective degradation occurred for both pharmaceuticals during wastewater treatment. Ibuprofen showed enantioselective degradation in the anaerobic, anoxic, and aerobic conditions, whereas iopromide displayed isomer-selective degradation only under the aerobic condition. In the river waters, the EF of ibuprofen was 0.130–0.327 and the IR of iopromide was 1.500–2.531. The results suggested that pharmaceuticals in the mainstream Pearl River were mainly from discharge of treated wastewater, whereas in the tributary rivers and urban canals, direct discharge of untreated wastewater represented a significant contribution. The IR of iopromide can be an applicable and efficient tracer for wastewater discharge in the environment.     

Spatial distribution,pollution level,and health risk of Pb in the finer dust of residential areas: a case study of Xi'an,northwest China

Environmental Geochemistry and Health - The spatial distribution, pollution level, and exposure risk of Pb in the finer dust (particle size?&lt;?63&nbsp;μm) of residential...     

臭氧对南方3种木本植物的急性伤害症状及其生理指标变化

近地层O3污染越来越严重,而O3污染对中国木本植物的影响的报道较少。作者对南方3种木本植物尾叶桉(Eucalyptusurophylla)、米兰(Aglaiaodorata)和马尾松(Pinusmassoniana)进行连续3d,每天6h的O3熏气处理。臭氧体积分数分别为200×10-9和400×10-9。实验过程中对植物的外部受害症状进行观察记录,测定叶片的叶绿素含量、过氧化物酶活性(POD)、过氧化氢酶活性(CAT)、丙二醛含量(MDA)、可溶性糖含量和可溶性蛋白质含量等生理指标。结果表明:3种植物对O3污染表现出不同的受害症状。受O3污染危害最重的为米兰,其次为尾叶桉,而马尾松抗性最强。O3污染导致植物叶绿素含量、可溶性糖含量呈下降趋势,而POD活性升高,少数种类则出现微弱的下降趋势。CAT基本表现为低浓度O3污染时活性上升,在高浓度时,由于酶的结构受破坏,而出现下降的趋势,但也有的种类是外部臭氧浓度越高,则CAT含量越高。丙二醛含量则是多数情况比对照升高,而某个种类变化不明显或稍有下降。可溶性蛋白含量是在低浓度O3污染时有所上升,而高浓度时则出现下降的情况。研究结果表明,在评价不同植物种类对污染物的抗性时,不能仅考虑某个生理指标的变化,还要综合考虑各个指标的状况。     

PAHs in surface sediments from coastal and estuarine areas of the northern Bohai and Yellow Seas, China

Polycyclic aromatic hydrocarbon (PAH) concentrations and their risks in surface sediments (n = 35) collected from coastal and estuarine areas of the northern Bohai and Yellow Seas, China, were investigated in 2008. Total concentrations of PAHs ranged from 52.3 to 1,870.6 ng/g dry weight. The greatest concentrations were observed in the Dou River of Tangshan where waste water from small factories is discharged into the river without treatment. At other locations, municipal sewage was the primary contributor of PAHs. Regional differences in concentrations of PAHs in sediments are related to human activities. Concentrations of PAHs were significantly correlated with concentrations of organic carbon in sediments. The patterns of relative concentrations and types of PAHs observed and knowledge of the potential sources, as well as the results of a principal component analysis, are consistent with the primary sources of PAHs in sediments of the northern Bohai Sea and Yellow Sea, being derived from the high-temperature pyrolytic processes such as combustion of fossil fuel. While concentrations of PAHs at most locations did not exceed the effects range median stated by the numerical effect-based sediment quality guidelines of the United States, concentrations of PAHs at some locations were similar to or greater than the effects range low.